Rear projection screen

Abstract

The present invention relates to a rear projection screen ( 1 ) for allowing an observer to view an image at a front side by receiving light projected at a rear side. The rear projection screen comprises a transparent plate ( 3 ); an optical sheet ( 8; 8 ′) which is hot-pressed on a rear surface of the transparent plate ( 3 ) and includes a plurality of fine prisms ( 5; 5 ′) formed from side to side and parallel to one another to refract the light and guide the refracted light to the front side, each fine prism protruding to the rear side; a diffusion film ( 20 ) which is bonded to a front surface of the transparent plate ( 3 ) and including a transparent film ( 2 ) and diffusion layers ( 6 ) formed on front and rear surfaces of the transparent film to omnidirectionally disperse and diffuse the light refracted through the optical sheet ( 8; 8 ′); and light-shielding printed layers ( 4 ) which are formed on an upper surface of the diffusion layer ( 6 ) to be horizontally parallel to one another and face portions between the fine prisms ( 5; 5 ′) of the optical sheet ( 8; 8 ′). According to the rear projection screen of the present invention so configured, there is no reflected image on a surface on the side of an observer even under a bright environment such as the presence of sunlight, and a extremely precise color image with a high black level can be obtained. Further, a large-sized screen with less light loss can be manufactured at a low cost by first refracting light emitted from a projector through a fine prism optical sheet and then diffusing the refracted light.

1 . A rear projection screen for allowing an observer to view an image at a front side by receiving light projected at a rear side, comprising: 
 a transparent plate;    an optical sheet hot-pressed on a rear surface of the transparent plate, the optical sheet comprising a plurality of fine prisms formed from side to side and parallel to one another to refract the light and guide the refracted light to the front side, each of the fine prisms protruding to the rear side;    a diffusion film bonded to a front surface of the transparent plate, the diffusion film comprising a transparent film and diffusion layers formed on front and rear surfaces of the transparent film to omnidirectionally disperse and diffuse the light refracted through the optical sheet; and    light-shielding printed layers formed on an upper surface of the diffusion layer to be horizontally parallel to one another, the light-shielding printed layers facing portions between the fine prisms of the optical sheet.    
   
   
       2 . The rear projection screen as claimed in  claim 1 , wherein the screen has fine aspherical lens layers formed to be elongated between the light-shielding printed layers.  
   
   
       3 . The rear projection screen as claimed in  claim 1 , wherein the fine prisms have a fixed angle with respect to the rear surface of the transparent plate.  
   
   
       4 . The rear projection screen as claimed in  claim 2 , wherein the fine prisms have a fixed angle with respect to the rear surface of the transparent plate.  
   
   
       5 . The rear projection screen as claimed in  claim 1 , wherein the fine prisms are different-angle fine prisms of which the angles defined with respect to the rear surface of the transparent plate consecutively vary within a range of 5 to 65 degrees in a vertical direction to form a gradient as a whole.  
   
   
       6 . The rear projection screen as claimed in  claim 2 , wherein the fine prisms are different-angle fine prisms of which the angles defined with respect to the rear surface of the transparent plate consecutively vary within a range of 5 to 65 degrees in a vertical direction to form a gradient as a whole.  
   
   
       7 . The rear projection screen as claimed in  claim 1 , wherein the diffusion layer of the diffusion film is formed by coating and drying a solution with white powder and an acrylic binder mixed therein.  
   
   
       8 . The rear projection screen as claimed in  claim 2 , wherein the diffusion layer of the diffusion film is formed by coating and drying a solution with white powder and an acrylic binder mixed therein.  
   
   
       9 . The rear projection screen as claimed in  claim 3 , wherein the diffusion layer of the diffusion film is formed by coating and drying a solution with white powder and an acrylic binder mixed therein.  
   
   
       10 . The rear projection screen as claimed in  claim 4 , wherein the diffusion layer of the diffusion film is formed by coating and drying a solution with white powder and an acrylic binder mixed therein.  
   
   
       11 . The rear projection screen as claimed in  claim 5 , wherein the diffusion layer of the diffusion film is formed by coating and drying a solution with white powder and an acrylic binder mixed therein.  
   
   
       12 . The rear projection screen as claimed in  claim 6 , wherein the diffusion layer of the diffusion film is formed by coating and drying a solution with white powder and an acrylic binder mixed therein.  
   
   
       13 . The rear projection screen as claimed in  claim 7 , wherein the white powder is selected from the group consisting of titanium dioxide, silica, calcium carbonate, aluminum hydroxide, or a combination thereof.  
   
   
       14 . The rear projection screen as claimed in  claim 8 , wherein the white powder is selected from the group consisting of titanium dioxide, silica, calcium carbonate, aluminum hydroxide, or a combination thereof.  
   
   
       15 . The rear projection screen as claimed in  claim 9 , wherein the white powder is selected from the group consisting of titanium dioxide, silica, calcium carbonate, aluminum hydroxide, or a combination thereof.  
   
   
       16 . The rear projection screen as claimed in  claim 10 , wherein the white powder is selected from the group consisting of titanium dioxide, silica, calcium carbonate, aluminum hydroxide, or a combination thereof.  
   
   
       17 . The rear projection screen as claimed in  claim 11 , wherein the white powder is selected from the group consisting of titanium dioxide, silica, calcium carbonate, aluminum hydroxide, or a combination thereof.  
   
   
       18 . The rear projection screen as claimed in  claim 12 , wherein the white powder is selected from the group consisting of titanium dioxide, silica, calcium carbonate, aluminum hydroxide, or a combination thereof.